A debtor may contest the findings of the investigation as to the validity and the amount of the debt in a hearing before the Central Collection Unit. Any request for a hearing shall be submitted in writing to the Central Collection Unit within 30 days of the date of which the investigation report was mailed to the debtor. In the hearing before the Central Collection Unit, the debtor may not raise any issue regarding the amount of tax refund otherwise due the taxpayer. This restriction does not prejudice any rights available to the debtor under the tax laws. The Central Collection Unit may deny a request for a hearing if the: Appeal is not filed timely and no good cause for the delay is shown; Issues raised in the appeal have been adjudicated by a court; or Issues raised in an intercept appeal have been adjudicated on an appeal of the certification and no new law or evidence has been introduced. Conduct of Hearings. Within 15 days of receipt of a timely request for a hearing, the debtor shall be notified of the hearing date. The Central Collection Unit shall designate the place for a hearing and shall notify the appellant of it at least 5 days in advance. If the appellant notifies the review officer that either the date or place designated is not convenient and requests a new date or place for the hearing and gives a valid reason for so requesting, the review officer may designate another date and place. The debtor may waive an oral hearing date, in which case the hearing shall be conducted by a review of the record. A review of the record shall consist of a review of the relevant collection records and any written evidence submitted by the debtor. At any hearing, the debtor has the right to have an attorney or other representative present to assist him. The debtor has the right to present witnesses, documentary evidence, and oral argument, and to examine any documents presented by others as evidence at the hearing and to cross-examine any witness. The debtor may not raise any issues in the hearing that have been previously litigated, whether in court or in an administrative hearing. The review officer shall make a record, containing the substance of what happened at the hearing, to be retained by the Central Collection Unit. This record, together with all papers filed in the proceedings and the review officer's findings and conclusions, and decisions, constitutes the exclusive record and shall be available for review by the debtor or representative at any reasonable time for a period of 2 years or until all litigation on the intercept is ended, whichever is greater. The State agency which referred the debt to the Central Collection Unit may participate in the hearing. A hearing request may be withdrawn by the debtor or representative at any time. A hearing request is considered abandoned if the debtor and his representative fail to appear at the hearing and fail to notify the Central Collection Unit within 5 days of the original hearing date of a desire to pursue the appeal. Decisions. The review officer shall prepare a written summary of findings of fact and conclusions of law based exclusively on the record and shall make a decision upon those findings. The date of the hearing is the date for calculating the amount of any debt considered in the decision. If, in the case of a hearing on certification, the review officer finds that the debtor is incorrectly certified, the review officer shall instruct the Comptroller to delete the debtor's name from the certification list, or to reduce the amount of certified debt, whichever is appropriate. In the case of a hearing on an intercept, if the review officer decides that no debt exists, the Central Collection Unit shall pay the full tax refund to the taxpayer within 5 days of the date of that determination. If the review officer determines that the tax refund remitted to the Central Collection Unit is in excess of the amount of the debt, the Central Collection Unit shall return the excess to the debtor within 30 days of the date of the decision. Judicial Appeal. A taxpayer may appeal the review officer's decision in accordance with the Administrative Procedure Act.